From patchwork Mon Jan 26 15:49:59 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 3997 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n0QFo2Q2031764 for ; Mon, 26 Jan 2009 15:50:02 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751332AbZAZPt7 (ORCPT ); Mon, 26 Jan 2009 10:49:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751422AbZAZPt7 (ORCPT ); Mon, 26 Jan 2009 10:49:59 -0500 Received: from gecko.sbs.de ([194.138.37.40]:16779 "EHLO gecko.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbZAZPt7 (ORCPT ); Mon, 26 Jan 2009 10:49:59 -0500 Received: from mail1.sbs.de (localhost [127.0.0.1]) by gecko.sbs.de (8.12.11.20060308/8.12.11) with ESMTP id n0QFnuP2013419 for ; Mon, 26 Jan 2009 16:49:56 +0100 Received: from [139.25.109.167] (mchn012c.mchp.siemens.de [139.25.109.167] (may be forged)) by mail1.sbs.de (8.12.11.20060308/8.12.11) with ESMTP id n0QFnuIv008721 for ; Mon, 26 Jan 2009 16:49:56 +0100 Message-ID: <497DDBA7.1040103@siemens.com> Date: Mon, 26 Jan 2009 16:49:59 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: kvm-devel Subject: x86: Corrupted eflags in qemu's CPU state Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi, this line almost ruined my afternoon: The guest flags reported via gdb or monitor were garbage and I first didn't realized this... git logs revealed that commit 6eecdc3eea74ead3c11b8b43d825d2cabe7a2456 once introduced it mid of 2006, but maybe under different boundary conditions. At least today it appears to be plain wrong, eflags must always contain to full state, cc_src, df & cc_op are just supplementary states. Please correct me if I'm wrong, otherwise I will send out a proper patch, also upstream as QEMU's kvm suffers from the same issue. Jan diff --git a/qemu/qemu-kvm-x86.c b/qemu/qemu-kvm-x86.c index 01748ed..4ad386b 100644 --- a/qemu/qemu-kvm-x86.c +++ b/qemu/qemu-kvm-x86.c @@ -429,7 +429,6 @@ void kvm_arch_save_regs(CPUState *env) env->cc_src = env->eflags & (CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C); env->df = 1 - (2 * ((env->eflags >> 10) & 1)); env->cc_op = CC_OP_EFLAGS; - env->eflags &= ~(DF_MASK | CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C); /* msrs */ n = 0;